CSS problemas no IE 6

Olá estou com problema no IE 6, o que poderia esta causado este erro a parte do codigo que estou usado que esta com erro este logo abaixo.

O endereço do site e este aqui. www.hotnx.com.br

/ ---------------------- Dolphin nav ---------------------- /

#dolphincontainer{
	position:relative;
	width:936px;
	background-image: url(../img/layout/dolphin_bg.gif);
}
#dolphinnav{
	position:relative;
	height:29px;
	font-size:11px;
	text-transform:uppercase;
	background-image: url(../img/layout/dolphin_bg.gif);
	background-repeat: repeat-x;
	background-position: left bottom;
	padding-top: 0;
	padding-right: 0;
	padding-bottom: 0;
	padding-left: 6px;
}

#dolphinnav ul{margin:0;padding:0;list-style-type:none;width:auto;float:left;}
#dolphinnav ul li{display:block;float:left;margin:0 0px;}
#dolphinnav ul li a{display:block;float:left;color:#000000;text-decoration:none;padding:0 0 0 3px;height:29px;}
#dolphinnav ul li a span{padding:7px 6px 0 0;height:6px;float:left;}
#dolphinnav ul li a:hover{color:#fff;background:transparent url(../img/layout/dolphin_bg-OVER.gif) repeat-x bottom left;}
#dolphinnav ul li a:hover span{display:block;width:auto;cursor:pointer;}
#dolphinnav ul li a.current,#dolphinnav ul li a.current:hover{color:#fff;background:#1D6893 url(../img/layout/dolphin_left-ON.gif) no-repeat top left;line-height:275%;}
#dolphinnav ul li a.current span{display:block;padding:0 5px 0 0;width:auto;background:#1D6893 url(../img/layout/dolphin_right-ON.gif) no-repeat top right;height:29px;}
/ ---------------------- END Dolphin nav ---------------------- /